Carbureter.



W. W. MUIR.

GARBURETER.

APPLICATION FILED APR. 22, 1913.

1,078,592, Patented Nov. 11, 1913.

2 SHEETS-SHEET 1.

W. W. MUIR.

CARBURETER.

APPLICATION FILED APR.22, 191a.

Patented Nov. 11, 1913.

2 SHEBTBSHEET 2.

WELLINGTON W. MUIB,

INCORPORATED, 013 BALTIMORE, MARYLAND, A. CORPORATION 015 OF BALTIMORE, MABYLAKD, ASSIG'NOB T0 MUIIB. COMPANY,

DELAWARE.

GAEB'URETEE.

Specification of Letters Patent.

Patented Nov. 11. 1913.

Application filed April 22, 1913. Serial No. 762,951.

To all 107mm 2'1. may concern:

Bait known that LWELLINGTON W. More, a citizen of the United States of America residing at the city of Baltimore, State 0 is capable of being used with the most volatile of liquid fuels, is particularly well adapted for usewith the heavier fuels as kerosene. crudeoil and the like.

Broadly considered, it consists of an atomizing or aspirating nozzle for spraying or aspirating the fuel, the nozzle being located in the inlet or supply passage leading to the inlet port or ports of the engine and placed between the throttle and the cylinder so that the nozzle is subject to the full vacuum of the engine in combination with a passage connecting the nozzle to the outside air and means for feeding fuel into the passage. v Preferably the nozzle is fed by a fine suction passage or tube which at the end remote from the nozzle is enlarged and freely supplied with air at the prevailing atmospheric pressure. The liquid fuel is in troduced into the tube and is atomized by the action of the air as it passes through the tube and escapes from the nozzle propelled by the full vacuumof the engine.

In the preferred form of the device the liquid fuel is supplied to the enlarged portion of the suction tube and the fuel feed is controlled by the flow of air or mixture to the combustion chamber. This may be accomplished in any convenient manner. In the present instance an air float is used which may be placed at any desired point in the supply passage by which the charge'is led to the combustion chamber either. in the carbureter or elsewhere in the passage.

An important feature of the device thus described is that in operation the velocity at the aspirating nozzle and hence the tendency to feed and spray the fuel instead of decreasing in the normal operation of the engine at low speed is increased when the throttle is closed so that the tendency to produce a weak mixture and stall the engine at low throttle is completely overcome. This is particularly important-in the use of heavy fuels which are apt to fail at low speeds and low throttle because the draft in the carbureter is insufficient to give a suitable aspi' rating efiech Another important feature of the device resides in the manner of suppl ing fuel to the suction passage. This feed is essentially a gravity feed, the suction passage at the point atwhich the liquid fuel is introduced being of suficient cross-section to practi' Cally eliminate all tendency to produce a vacuum at this point due to the velocity of the air.

One. of the principal difliculties encountered in the use of heavy fuels in internal combustion engines is that which occurs in starting, and the present device is particularly adapted to overcome that difiiculty. To this end the suction-tube is preferably formed with a depressed portion sufficient to contain a priming charge of fuel. This depressed portion fills up to the level of the fuel in the float chamber while the engine is idle, and then when the engine is turned over and the piston moves backward on the intake stroke, the vacuum created in the cylinder causes a rush of air through the suction tube, atomizing the charge and blowing it into the cylinder so that an eficient priming charge is thus delivered.

To feedithe priming charge, the valve is so placed that it is never positively seated but. even at its lowest position it is very slightly spaced from t e valve opening. Also the throttle is 50 arranged that when the engine is running idle, and during starting, 2'. a, at low throttle, it is fully closed so the entire charge of air and fuel comes through thesuc'tion tube. This gives a rich mixture and improves the delivery of the fuel at low speed and low throttle, so that stalling of the engine under these circumstances is practically impossible.

In the accompanying drawing T have illustrated acarbureter embodying my invention in its preferred form. Figure 1 is a plan of the carbureter detached. Fig. 2 is a vertical central section on the line 2, 2 of Fig. 1. Fig. 3 is a fragmentary vertical section on the line 3,3 of the same figure. Fig. 4 is a vertical central section corresponding to Fig. 2 showing a slightly modified form of the invention.

Referring to the drawing by numerals, each of which is used to indicate the same or equivalent parts in the different figures of the drawings, the carbureter includes the v ing aperture 16 in the cover, the enlarged usual float chamber 1, the level of the fuel in which is controlled by means of a float 2 operating asuitable inlet valve not shown. It also includes the air passage 3 and the aspirating nozzle 5 fed by the suction passage 4. The air passage is controlled by meansof a suitable throttle valve 6 operated'manually or otherwise through a lever 7. This throttleis peculiar in that it is fully closed at "low throttle position.

An important feature of the invention resides in the placing of the fuel nozzle'5 in the passage 3 between the throttle and the delivery opening 8, 2'. el, between the throttle and the engine port. 4

The fuel is,fed from the float chamber 1 to the suction'passage 4 by way of the gravity feed opening 9 shown as having a knifeedge periphery to improve the feed of viscous fuel. This opening is controlled by'the needle valve 10 operated in any suitable manner preferably as hereinafter described. In its lowest position this valve is slightly spaced from the opening 9 or otherwise leaves a slight valve opening. In this connection it will be noted that while the nozzle end of the suction passage 4, as shown, is of comparatively small and constricted area, it is enlarged where the fuel is delivered, forming a fuel chamber 11, and that from this chamber 11 to the inlet opening 12 the passage is of ample cross-section many times that of the nozzle end of the passage. This is for the purpose of giving free access of air to the fuel chamber 11 so that the feed of the fuel shall be in nowise accelerated or retarded as the suction of the engine varies and shall be in fact a gravity feed. The proportion of the passage by which air and fuel are supplied to the aspirating nozzle is preferably depressed as shown so that the passage as a whole may be properly termedU- shaped, the mouth being at the end of one upright arm of the U and the nozzle at the end of the other corresponding arm. As thus formed, the passage serves to retain a supply of fuel which accumulates when the engine is idle, and this serves as a priming charge as hereinafter described.

In the preferred form of the invention the valve 10 is constructed as shown, being mounted to slide in a suitable bearing and guide 13 in the cover 14 of the float chamber. In the valve as shown the stem is enlarged above the needle proper at 15, and this enlarged portion slides in a correspondportion 15 being reduced and shouldered at 18 to form a seat for the spring 19 hearing againsta screw-cap 20 whichcloses the aperture in. the cover. The cover 15 of the valve is slotted in a transverse direction at 21, and through this slotted portion extends a cam er'ated to the valve.

member 22 carried on the stem 23 of an air float 24 located at any preferred point in the supply passage so that it will be actuated by the suction. In the device as shown a light helical spring 25 tends to maintain the float 24 on its seat, but the spring 25 is so light that the tendency of the float 24: to check the flow of the air is very slight and substantially negligible.

The needle valve 10 is provided with any suitable follower device as that numbered 26 extending into the slot 21 to engage the cam 22 and transmit the motion thus gen- This follower as shown is carried by a screw 27 mounted in a suitably threaded aperture 28 in the valve stem extending axially inward from the end of the valve stem to the slot 21 whereby suitable adjustment of the valve relatively to the cam is provided. For the purpose of locking the screw in adjusted position, a springpressed ball 30 engaging suitable seats in the walls of the screw-hole in the valve is provided.

If it is desired to heat the fuel slightly to decrease its viscosity, this may be done to good advantage by means of an electric heating coil 31 encircling the suction pipe 4.

In Fig. 4 I have shown a slightly differout form in which the throttle valve 33 instead of being placed inside the carbureter in the air passage 3 is placed outside and beyond the air float 24. This form of the device is introduced merely for the purpose of showing that the relative positions of the throttle and the air float are immaterial, and in regard to these elements of the device it is only important that the fuel nozzle should be placed between the throttle and the engine ports so that it is subject to the suction of the engine and to the full vacuum thus generated.

The operation of the device has been disclosed in the preamble and specification:

The float 2 controlling the supply of fluid to the chamber 1 maintains the liquid at a predetermined level therein as indicated by the dotted line shown extending across the chamber in the drawing. The valve 10 is so constructed as to permit the passage of a small amount of the fluid even when in closed position, so that if the engine is idle for any considerable. period suflicient to permit it to become cool, the liquid will collect in the suction tube to the level of the liquid in the float chamber. The fuel so collected serves as a priming charge, and when the engine is turned over for starting, the throttle being preferably closed, the suction of the engine draws a quantity of air in the mouth 12 of the suction pipe, and this air with the fuel passing out of the nozzle 5 produces a fine spray of highly inflammabb character and forms aivery eflicient starting charge so that in the normal operatim of the carbureter, priming isthus lcmllplished automatlcally. The charge It 10' efl'ective spraying Lemma determines the position of the fuel valve l ent of the suction, for it 10 so that the greater the power developed and required, the greater the supply of fuel, and this supply is in turn wholly independis delivered not at the engine pressure but at the pressure of the outside air as admitted through the wide mouth 12 of the suction tube. The

actual operation consists in utilizing the vacuum of the engine to draw a small quantity of air through the nozzle into the supply passage ata point between the throttle and the cylinder, and supplying fuel to this attenuated air current so it is atomized thereby, the fuel being actually interposed in the path of the current so that all the fuel fed is necessarily carried along by the air and atomized by it. fhus while the extent of the fuel supply is wholly unaffected by the suction of the engine, the actual draft and spraying effect is not only dependent thereon but is increased as the throttleis closed and the speed of the engine conse quently reduced. In this way the spraying of the heavy fuel at low throttle is rendered more eficient and thorough than it is at full throttle, and the tendency of the engine to stop at low throttle due to inefiective presentation of the charge at this time is wholly overcome."

l have thus described specifically a single embodiment of my invention in order that its nature and operation may be clearly unea c, the earburetin'gpassage derstood. However, the specific terms herein are used. in their descriptive rather than in their limiting sense and the scope of the invention is defined in the claims. 1 t claimr l. A carburetor consisting of means for maintaining a. constant a carburetin passage, a U-shaped passage, one leg of t being enlarged, the other being of reduced cross-section, a nozzle at the end of thereduced portion and the carbureting- I pas leading to the in ct portpithe engine and 0 en at one end dniitgair, a-throttle: in 't e. assage so hat the nozzleisbetween t ethrottle engine .portgland a gravity. feed for drop ing passage,

23 carrying the cam 22 maintaining a constant hea head of liquid fuel, I "a; carbnreting e 'lJ'froIn the base to the top duced portion and fuel intulthe enlarged portion of Y the shaped passage,"the s ze of the enlarged portion of the U-shaped passage beeliminate any perceptible ing such as to of such vacuum on vacuum thereinor effect the flow ofthe fuel.

' 2. A carbureter consisting of a carbureta U-shaped passage, one leg of the U from the base to the top being enlarged, the other being of reduced crosssection, a nozzle at the end of the reduced portion and in the carbureting passage, the carbureting passage leading to the inlet port of the engine and open at one end to admit air, a throttle in the passage so placed that the nozzle is between the throttle and the engine port, a gravity feed for dropping fuel into the enlarged portion" "of the U- shaped passage, the size of the enlarged portion of the lf-shaped passage being such as to eliminate any perceptible vacuum therein or eifect of such vacuum on the flow of the fuel, a fuel valve and means for controlling the position of the valve consisting of an air float in the passa e leading to the inlet port of the engine, an means for communicating the motion of the float to the fuel valve.

3. A earbui-eter consisting of means for maintaining a constant head of liquid fuel, a carbureting passage, a U-shaped'passage, one leg of the U from the base to the top being enlarged, the other being of reduced cross-section, a nozzle at the end of the reduced portion and in the carbureting passage, the carbureting passage leading to the inlet port of the engine and open at one end to admit air, a throttle in the passage so placed that the nozzle is between the throttle and the engine port, pin fuel into the nlarged portion of the U-s aped passage, the size of the enlarged portion of the U- haped passage being such as to eliminate any perceptible vacuum 1 therein or effect of such vacuum on the flow a gravity feed for drop of the fuel, afuel valve controlling the grav' ity feed, a follower thereon, an anfloat 1n thepassage leading to the engine port, and

a cam ri idly thefloat to be engaged y the folloyver. the valve and g the level of the fuel means for maintainin well abovethe bottom of the U shaped passa e.

A of means for of liquid fuel, passage, a U= haped passage, one leg of t e U from the base to the top being enlarged, the other being of reduced crosssection, a nozzle at'the end of the rein the carbureting pas sage, the carburetin'g passage leading to the inlet port of the engine and open at one end to admitair, 'a throttle in the passage so placed that the nozzle is between the throttleand the engine port,a gravity feed for droppjing fuelvinto-the enlarged portion of the -shaped passage, the size of the enlarged portion of the U- haped passage being such carburetor consisting as to eliminate any perceptible vacuum therein or effect of such vacuum on the flow of the fuel, a fuel valve controlling the grav ity feed, an air float in the passage leading to the supply port of the engine, means rigidly connected to the float and means rigidly connected to the valve engaging said means whereby the motion of the float in a modified form is communicated to the fuel valve.

5. In a constant level carburetor, an air passage, a throttle, a fuel nozzle in the air passage between the throttle and the supply port of the engine, a suction passage leading to the nozzle and open at its opposite end to the outside air, the open end being enlarged and a gravity feed for feeding gasolene into the enlarged portion of the passage, the remainder of the passage being so reduced that the vacuum in the enlarged portion of the passage is negligible and the air pressure at the point where the fuel is fedis substantially equal to that of the outside air. 6. In a carbureter, an air passage, a throttle, a fuel nozzle in the passage between the throttle and the supply port of the engine, a suction passage leading to the nozzle and open at its opposite end to the outside air, the open end being enlar ed so that the vacuum iii the passage is su stantially eliminated and means for feeding gasolene to the enlarged ortion of the passage, the suctio-n passage eing depressed intermediately of its length to form a receptacle for the fuel, the remainder of the passage between the enlarged portion and the nozzle being so reduced that the air pressure at the point at which the gasolene is fed to the passage is substantially equal to 'the pressure of the outside air.

7. In a carbureter, an air passage, athrottie, a fuel nozzle in the passage between the 7/ throttle and the supply port of the engine, a suction passage leading to the nozzle and open at its opposite end to the outside air, the open end being enlarged, and the remainder of the passage between the enlarged portion and the nozzle being reduced so that the vacuum in the enlarged portion is practically eliminated, the reduced portion joining the enlarged portion near the lowest point thereof, a gravity feed for feeding gasolene to the enlarged portion of the assage, a valve for controlling the fuel eed and means for operating the valve in the form of an air float in the air passage, a

cam connected to the air float and a follower on the valve engaging the cam.

8. In a carbureter, means for maintaining the liquid fuel at a constant level, an air passage, a throttle, a fuel nozzle in the passage between the throttle and the supply port of the engine, a suction passage leading to the nozzle and open at its opposite end to the outside air, the open end being enlarged, the remainder of the passage between the enlarged portion and the nozzle being reduced so that the vacuum in the portion is substantially eliminated, the re duced portion joining the enlarged portion near the lowest point thereof, a gravity feed for feeding liquid to the enlarged portion of the passage, a valve for controlling the fuel feed and means for operating the valve in the form of an air float in the air passage, and means for transmitting motion from the air float to the fuel valve.

Signed by me at Baltimore, this 21st day of April, 1913. v WELLINGTON W. Witnesses: I

EDWARD L. BASH, EDWIN F. SAMUnLs.

Maryland,

enlarged 

